Plastic cards used for a multitude of purposes are well known in the state of the art, the most well-known including payment by debit or credit card, credit cards or identification for buildings or various kinds of events. The frontal and rear faces of these plastic cards are usually decorated with all kinds of motifs, which usually constitute advertising and, on many occasions, contain some or all of the information required in order for them to fulfil their objective within this decoration, for example the name of the card holder.
One aesthetic requirement of decorated plastic cards is that their sides are the same color as their frontal and rear faces or other kinds of decoration wished to be incorporated.
In order to ensure that the sides of cards are the desired color, cards made of plastic of the desired color are used. This solution requires manufacturers to maintain stock in each one of the colors offered, therefore meaning the cost of maintaining this stock is very high. Furthermore, since storing cards in all colors is very costly, it is highly likely that they will lose out on sales opportunities simply because they don't have the color a client desires at any particular time.
The invention object of the present description offers a decoration technique, unpublished to date, for decorating the sides of plastic cards by means of the well-known hot foil stamping decoration method, the characteristics of this method making it possible to lower production and stock maintenance costs, thereby possibly meaning just one color of card needs to be stocked, which is usually white.
The hot foil stamping method consists of applying a certain amount of pressure using an engraver, during a certain period of time at a certain temperature, to a piece of foil located on the surface to be decorated.
The surface where the engraver comes into contact with the foil may be completely flat or have a relief of the symbol to be decorated engraved onto it. After hot stamping, it is possible to clean the foil traces by means of the blowing, brushing or transfer process, in order to eliminate the traces of foil that may be left behind.
Hot foil stamping is carried out, amongst other things, in vertical stamping machines and roll-on stamping machines.
Vertical hot stamping machines constitute vertical presses, the mobile body of which is an arm, which moves up and down alternately, there being a heater head piece at the end of said arm, to which an engraver that may be heated up is coupled, in addition to a support or wedge, which positions and holds the pieces to be stamped, as well as various feeder, transportation and placement devices for the foil and devices for controlling pressure, stamping time and the temperature at which the engraver is to be heated.
In roll-on stamping machines, the heater head piece is a cylinder that rotates on its own axis, to which the engraver that may be heated up is coupled on the external cylindrical surface thereof, this kind of machine being used to carry out large series stamping.
Hot stamping foil is formed by various layers that are deposited on a polyester support. In order, these layers include: polyester, a coating layer, a protective layer, a decorative layer or layers or color/aluminum layer and an adhesive layer, applied with heat and pressure.
It is applied using heat and pressure on the surface to be decorated, the relief with which the engraver is formed constituting the element that comes into physical contact with the foil, which is transferred to the surface.